boost/log/attributes/fallback_policy_fwd.hpp
/* * Copyright Andrey Semashev 2007 - 2015. * Distributed under the Boost Software License, Version 1.0. * (See accompanying file LICENSE_1_0.txt or copy at * http://www.boost.org/LICENSE_1_0.txt) */ /*! * \file fallback_policy_fwd.hpp * \author Andrey Semashev * \date 18.08.2012 * * The header contains forward declaration of fallback policies when attribute value visitation or extraction fails. */ #ifndef BOOST_LOG_ATTRIBUTES_FALLBACK_POLICY_FWD_HPP_INCLUDED_ #define BOOST_LOG_ATTRIBUTES_FALLBACK_POLICY_FWD_HPP_INCLUDED_ #include <boost/log/detail/config.hpp> #ifdef BOOST_HAS_PRAGMA_ONCE #pragma once #endif namespace boost { BOOST_LOG_OPEN_NAMESPACE /*! * The \c fallback_to_none policy results in returning an empty value reference if the attribute value cannot be extracted. */ struct fallback_to_none; /*! * The \c fallback_to_throw policy results in throwing an exception if the attribute value cannot be extracted. */ struct fallback_to_throw; /*! * The \c fallback_to_default policy results in a default value if the attribute value cannot be extracted. */ template< typename DefaultT > struct fallback_to_default; BOOST_LOG_CLOSE_NAMESPACE // namespace log } // namespace boost #endif // BOOST_LOG_ATTRIBUTES_FALLBACK_POLICY_FWD_HPP_INCLUDED_